...

cxx/mount.h

@@ -43,6 +43,12 @@ concept mcc_mount_state_c = requires(T t, const T t_const) {
     { t.enter() } -> std::same_as<void>;
     { t.exit() } -> std::same_as<void>;
     { t.stop() } -> std::same_as<void>;
+
+    typename T::state_data_t;
+
+    { t.stateData() } -> std::same_as<typename T::state_data_t>;
+
+    requires std::movable<T>;
 };
 
 }  // namespace traits
@@ -51,6 +57,46 @@ concept mcc_mount_state_c = requires(T t, const T t_const) {
 
 /*   SOME BASIC DATA STRUCTURES DEFINITIONS  */
 
+// coordinate system related constants
+enum class MccCoordKind : uint8_t {
+    COORDS_KIND_RA_IRCS,   // IRCS right ascension
+    COORDS_KIND_RA_APP,    // apparent right ascension
+    COORDS_KIND_HA,        // hour angle
+    COORDS_KIND_AZ,        // azimuth
+    COORDS_KIND_X,         // co-longitude coordinate
+    COORDS_KIND_DEC_IRCS,  // IRCS declination
+    COORDS_KIND_DEC_APP,   // apparent declination
+    COORDS_KIND_ALT,       // altitude
+    COORDS_KIND_ZD,        // zenithal distance
+    COORDS_KIND_Y          // co-latitude coordinate
+};
+
+enum class MccCoordPairKind : uint16_t {
+    // catalog's
+    COORDS_KIND_RADEC_IRCS = (int)MccCoordKind::COORDS_KIND_RA_IRCS + ((int)MccCoordKind::COORDS_KIND_DEC_IRCS << 8),
+    // apparent RA and DEC
+    COORDS_KIND_RADEC_APP = (int)MccCoordKind::COORDS_KIND_RA_APP + ((int)MccCoordKind::COORDS_KIND_DEC_APP << 8),
+    // apparent HA (hour angle) and DEC
+    COORDS_KIND_HADEC_APP = (int)MccCoordKind::COORDS_KIND_HA + ((int)MccCoordKind::COORDS_KIND_DEC_APP << 8),
+    // Azimuth and Altitude
+    COORDS_KIND_AZALT = (int)MccCoordKind::COORDS_KIND_AZ + ((int)MccCoordKind::COORDS_KIND_ALT << 8),
+    // Azimuth and Zenithal distance
+    COORDS_KIND_AZZD = (int)MccCoordKind::COORDS_KIND_AZ + ((int)MccCoordKind::COORDS_KIND_ZD << 8),
+    // co-longitude and co-latitude (e.g. mount hardware drive/axis encoders)
+    COORDS_KIND_XY = (int)MccCoordKind::COORDS_KIND_X + ((int)MccCoordKind::COORDS_KIND_Y << 8),
+};
+
+template <MccCoordPairKind KIND>
+static constexpr std::string_view MccCoordPairKindStr =
+    KIND == MccCoordPairKind::COORDS_KIND_RADEC_IRCS  ? "RADEC-IRCS"
+    : KIND == MccCoordPairKind::COORDS_KIND_RADEC_APP ? "RADEC-APP"
+    : KIND == MccCoordPairKind::COORDS_KIND_HADEC_APP ? "HADEC-APP"
+    : KIND == MccCoordPairKind::COORDS_KIND_AZALT     ? "Azimuth-Altitude"
+    : KIND == MccCoordPairKind::COORDS_KIND_AZZD      ? "AzimuthZendist"
+    : KIND == MccCoordPairKind::COORDS_KIND_XY        ? "XY"
+                                                      : "UNKNOWN";
+
+
 // meteo parameters (e.g. to compute refraction)
 struct MccMountMeteo {
     typedef double temp_t;
@@ -201,6 +247,31 @@ public:
         DT time_from{DT::min()};
     };
 
+
+    /*  mount state base class  */
+
+    class MccMountState
+    {
+    public:
+        MccMountState(MccMount& mount) : _mount(mount) {}
+
+        virtual ~MccMountState() = default;
+
+        void enter(this std::derived_from<MccMountState> auto&& self)
+        {
+            std::forward<decltype(self)>(self).enter();
+        }
+
+        void exit(std::derived_from<MccMountState> auto next_state)
+            requires std::movable<decltype(next_state)>
+        {
+            _mount.setMountState(std::move(next_state));
+        }
+
+    protected:
+        MccMount& _mount;
+    };
+
     /*  Constructors and destructor  */
 
     MccMount(traits::mcc_input_char_range auto const& logger_mark = "[MOUNT]",
@@ -229,7 +300,7 @@ public:
     /*  Public methods  */
 
     template <traits::mcc_mount_state_c StateT>
-    void setMountState(StateT& state)
+    void setMountState(StateT state)
     {
         _exitCurrentState();  // exit from current state
         _exitCurrentState = [&state]() { state.exit(); };